Abstract 16380: Disease Specific Induced Pluripotent Stem Cell Derived Cardiomyocytes Represent Pathophysiological Phenotype in Hypertrophic Cardiomyopathy

Abstract

Although hypertrophic cardiomyopathy (HCM) is a major hereditary heart disease, unknown underlying basic pathology make it difficult for physicians to heal this disease. We hypothesized that the disease specific iPS derived cardiomyocytes from HCM with the myosin binding protein C (MYBPC3) mutation represent the pathophysiological phenotype, and editing the mutation would cancel the diseased phenotype to check the role in the mutation gene. We established iPS cells with heterozygous frameshift mutation (WT/MT-iPS) from patient and performed genome editing to generate cells with repair of mutation (WT/WT-iPS) and homozygous mutation (MT/MT-iPS) using CRISPER-Cas9. Droplet digital PCR revealed that the transcript of the mutant allele was about 30% in WT/MT-iPS derived cardiomyocytes (CMs) compared to the WT allele and also WT/WT-iPSCMs and MT/MT-iPSCMs expressed only the transcript of WT allele and MT allele, respectively. The RNA expression of MYBPC3 was restored in WT/WT-iPSCMs and decreased in MT/MT-iPSCMs assessed by quantitative real-time PCR. Sarcomeric disarray was observed in WT/MT-iPSCMs, and was more prominently expressed in MT/MT-iPSCMs assessed by immunofluorescence staining. Cell motion analyzer revealed that relaxation velocity was significantly decreased and relaxation duration was significantly increased in WT/MT-iPSCMs and MT/MT-iPSCMs compared to WT/WT-iPSCMs. Moreover significant increase in contraction end velocity was observed in MT/MT-iPSCMs compared to WT/MT and WT/WT-iPSCMs. Established disease specific iPS-CMs with MYBPC3 mutation reproduces pathophysiology in HCM, providing important clues that elucidate true nature in patient’s hereditary diseases.